Higher November 2017 Paper 5 Q10
10 ABCD is a quadrilateral.
AD = AB and CD = CB.

Not to scale
Prove that angle ADC is equal to angle ABC. [4]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| AD = AB [given] oe CD = CB [given] oe AC = AC (common) oe Congruent SSS | M3 | M2 for 2 correct statements with reason[s] or 3 correct but no/incorrect reason[s] M1 for 1 correct statement with reason or 2 correct but no/incorrect reasons | |
| Angle ADC = angle ABC | A1 | If 0 scored, SC1 for AC is a line of symmetry oe or for triangle ADC is congruent to triangle ABC oe | Accept vertical line of symmetry or reflection see diagram as well if unsure |